/*
* Copyright 2002-2016 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.test.util;
import java.util.List;
import java.util.Map;
import com.jayway.jsonpath.JsonPath;
import org.hamcrest.Matcher;
import org.springframework.util.Assert;
import org.springframework.util.ObjectUtils;
import org.springframework.util.StringUtils;
import static org.hamcrest.MatcherAssert.*;
import static org.hamcrest.core.IsInstanceOf.*;
import static org.springframework.test.util.AssertionErrors.*;
/**
* A helper class for applying assertions via JSON path expressions.
*
* <p>Based on the <a href="https://github.com/jayway/JsonPath">JsonPath</a>
* project: requiring version 0.9+, with 1.1+ strongly recommended.
*
* @author Rossen Stoyanchev
* @author Juergen Hoeller
* @author Craig Andrews
* @author Sam Brannen
* @since 3.2
*/
public class JsonPathExpectationsHelper {
private final String expression;
private final JsonPath jsonPath;
/**
* Construct a new {@code JsonPathExpectationsHelper}.
* @param expression the {@link JsonPath} expression; never {@code null} or empty
* @param args arguments to parameterize the {@code JsonPath} expression with,
* using formatting specifiers defined in {@link String#format(String, Object...)}
*/
public JsonPathExpectationsHelper(String expression, Object... args) {
Assert.hasText(expression, "expression must not be null or empty");
this.expression = String.format(expression, args);
this.jsonPath = JsonPath.compile(this.expression);
}
/**
* Evaluate the JSON path expression against the supplied {@code content}
* and assert the resulting value with the given {@code Matcher}.
* @param content the JSON content
* @param matcher the matcher with which to assert the result
*/
@SuppressWarnings("unchecked")
public <T> void assertValue(String content, Matcher<T> matcher) {
T value = (T) evaluateJsonPath(content);
assertThat("JSON path \"" + this.expression + "\"", value, matcher);
}
/**
* An overloaded variant of {@link #assertValue(String, Matcher)} that also
* accepts a target type for the resulting value. This can be useful for
* matching numbers reliably for example coercing an integer into a double.
* @param content the JSON content
* @param matcher the matcher with which to assert the result
* @param targetType a the expected type of the resulting value
* @since 4.3.3
*/
@SuppressWarnings("unchecked")
public <T> void assertValue(String content, Matcher<T> matcher, Class<T> targetType) {
T value = (T) evaluateJsonPath(content, targetType);
assertThat("JSON path \"" + this.expression + "\"", value, matcher);
}
/**
* Evaluate the JSON path expression against the supplied {@code content}
* and assert that the result is equal to the expected value.
* @param content the JSON content
* @param expectedValue the expected value
*/
public void assertValue(String content, Object expectedValue) {
Object actualValue = evaluateJsonPath(content);
if ((actualValue instanceof List) && !(expectedValue instanceof List)) {
@SuppressWarnings("rawtypes")
List actualValueList = (List) actualValue;
if (actualValueList.isEmpty()) {
fail("No matching value at JSON path \"" + this.expression + "\"");
}
if (actualValueList.size() != 1) {
fail("Got a list of values " + actualValue + " instead of the expected single value " + expectedValue);
}
actualValue = actualValueList.get(0);
}
else if (actualValue != null && expectedValue != null) {
if (!actualValue.getClass().equals(expectedValue.getClass())) {
actualValue = evaluateJsonPath(content, expectedValue.getClass());
}
}
assertEquals("JSON path \"" + this.expression + "\"", expectedValue, actualValue);
}
/**
* Evaluate the JSON path expression against the supplied {@code content}
* and assert that the resulting value is a {@link String}.
* @param content the JSON content
* @since 4.2.1
*/
public void assertValueIsString(String content) {
Object value = assertExistsAndReturn(content);
assertThat(failureReason("a string", value), value, instanceOf(String.class));
}
/**
* Evaluate the JSON path expression against the supplied {@code content}
* and assert that the resulting value is a {@link Boolean}.
* @param content the JSON content
* @since 4.2.1
*/
public void assertValueIsBoolean(String content) {
Object value = assertExistsAndReturn(content);
assertThat(failureReason("a boolean", value), value, instanceOf(Boolean.class));
}
/**
* Evaluate the JSON path expression against the supplied {@code content}
* and assert that the resulting value is a {@link Number}.
* @param content the JSON content
* @since 4.2.1
*/
public void assertValueIsNumber(String content) {
Object value = assertExistsAndReturn(content);
assertThat(failureReason("a number", value), value, instanceOf(Number.class));
}
/**
* Evaluate the JSON path expression against the supplied {@code content}
* and assert that the resulting value is an array.
* @param content the JSON content
*/
public void assertValueIsArray(String content) {
Object value = assertExistsAndReturn(content);
assertThat(failureReason("an array", value), value, instanceOf(List.class));
}
/**
* Evaluate the JSON path expression against the supplied {@code content}
* and assert that the resulting value is a {@link Map}.
* @param content the JSON content
* @since 4.2.1
*/
public void assertValueIsMap(String content) {
Object value = assertExistsAndReturn(content);
assertThat(failureReason("a map", value), value, instanceOf(Map.class));
}
/**
* Evaluate the JSON path expression against the supplied {@code content}
* and assert that a non-null value exists at the given path.
* <p>If the JSON path expression is not
* {@linkplain JsonPath#isDefinite() definite}, this method asserts
* that the value at the given path is not <em>empty</em>.
* @param content the JSON content
*/
public void exists(String content) {
assertExistsAndReturn(content);
}
/**
* Evaluate the JSON path expression against the supplied {@code content}
* and assert that a value does not exist at the given path.
* <p>If the JSON path expression is not
* {@linkplain JsonPath#isDefinite() definite}, this method asserts
* that the value at the given path is <em>empty</em>.
* @param content the JSON content
*/
public void doesNotExist(String content) {
Object value;
try {
value = evaluateJsonPath(content);
}
catch (AssertionError ex) {
return;
}
String reason = failureReason("no value", value);
if (pathIsIndefinite() && value instanceof List) {
assertTrue(reason, ((List<?>) value).isEmpty());
}
else {
assertTrue(reason, (value == null));
}
}
/**
* Evaluate the JSON path expression against the supplied {@code content}
* and assert that an empty value exists at the given path.
* <p>For the semantics of <em>empty</em>, consult the Javadoc for
* {@link ObjectUtils#isEmpty(Object)}.
* @param content the JSON content
*/
public void assertValueIsEmpty(String content) {
Object value = evaluateJsonPath(content);
assertTrue(failureReason("an empty value", value), ObjectUtils.isEmpty(value));
}
/**
* Evaluate the JSON path expression against the supplied {@code content}
* and assert that a non-empty value exists at the given path.
* <p>For the semantics of <em>empty</em>, consult the Javadoc for
* {@link ObjectUtils#isEmpty(Object)}.
* @param content the JSON content
*/
public void assertValueIsNotEmpty(String content) {
Object value = evaluateJsonPath(content);
assertTrue(failureReason("a non-empty value", value), !ObjectUtils.isEmpty(value));
}
private String failureReason(String expectedDescription, Object value) {
return String.format("Expected %s at JSON path \"%s\" but found: %s", expectedDescription, this.expression,
ObjectUtils.nullSafeToString(StringUtils.quoteIfString(value)));
}
private Object evaluateJsonPath(String content) {
String message = "No value at JSON path \"" + this.expression + "\"";
try {
return this.jsonPath.read(content);
}
catch (Throwable ex) {
throw new AssertionError(message, ex);
}
}
private Object evaluateJsonPath(String content, Class<?> targetType) {
String message = "No value at JSON path \"" + this.expression + "\"";
try {
return JsonPath.parse(content).read(this.expression, targetType);
}
catch (Throwable ex) {
throw new AssertionError(message, ex);
}
}
private Object assertExistsAndReturn(String content) {
Object value = evaluateJsonPath(content);
String reason = "No value at JSON path \"" + this.expression + "\"";
assertTrue(reason, value != null);
if (pathIsIndefinite() && value instanceof List) {
assertTrue(reason, !((List<?>) value).isEmpty());
}
return value;
}
private boolean pathIsIndefinite() {
return !this.jsonPath.isDefinite();
}
}